Method for making a multi-channel magnetic head

ABSTRACT

A method of making a multi-channel magnetic head. A support plate having a flat surface is provided, and a magnetic core having a winding wound thereon is placed on said flat surface of said support plate in order to make an elementary unit. A plurality of said elementary units is stacked on one another, and said stacked elementary units are adhered to each other. The stack is cut into two halves in at least one plane which is perpendicular to the flat surfaces of said support plates and which divides each of the magnetic cores into two parts. The two halves are rejoined with a spacer between them with the core parts in one half matched with corresponding core parts in the other half.

Klnited States Patent [151 3,660,892 Tanaka et al. [451 May 9, 1972 [54] METHOD FOR MAKING A MULTI- 5 References Cited CHANNEL MAGNETIC HEAD UNITED STATES PATENTS 3,064 333 l 1/1962 Kristiansen et ..29/603 [72] Inventors. Takashi Tanaka, Yukihiro Yanagiuclu,

both ofosakajapan 3,545,077 l2/l970 Suzuki et al. ..29/603 Primary Examiner-John F. Campbell [73] Assignee: Matsushita Electric Industrial Co., Ltd., Assistant c Ha Kfldoma, Osaka, Japan Attorney-Wenderoth, Lind & Ponack [22] Filed: Aug. 28, 1970 [57] ABSTRACT [21] Appl. No.: 67,822 A method of making a multi-channel magnetic head. A support plate having a flat surface is provided, and a magnetic core having a winding wound thereon is placed on said flat [30] Foreign Application Priority Data surface of said support plate in order to make an elementary unit. A plurality of said elementary unitsis stacked on one Sept. 10, Japan another, and said Stacked elementa y units a e adh ed to July 6, 1970 Japan ..45/59262 each m The stack is cut into two halves in at least one plane which is perpendicular to the flat surfaces of said sup- [52] US. Cl ..29/603, 179/ 100.26 rt lat s a d which divides each of the magnetic cores into [51] Int. Cl. ....Gl1b 5/42, HOlf 7/06 two parts. The two halves are' rejoined with a spacer between [58] Field of Search ..29/603; 179/ 100.2 C; them with the core parts in one half matched with correspond- 340/174 F; 346/74 MC ing core parts in the other half.

5 Claims, 12 Drawing Figures PATENTED 9|973 3,660,892

' swan-1 e5 5 INVENTOR TAKASHI TANAKA YUKIHIRO YANAGIUCIII ATTORNEYS P'A'TE'N'TEBMAY 9 I972 SHEET 2 OF 5 FIG. 3

INVENTORS TAKASHI TAN/AKA YUKIHIRO YANAGIUCHI BY i 4 ma! ATTORNEYS PA'TE'NITEDMAY 9 I912 3,660,892

SHEET 3 a; 5

FIG. 6

INVENTORS TAKASH! TANAKA YUKIHI RO YANAGIUCHI ATTORNEYS PATENTEBMM 91912 8,660,892

SHEET u [3i 5 Fl 6. IO INVENTOR S TAKASHI TANAKA YUKI HI RO YANAGIUCHI ATTORNEYS PATENTEDMM 9W2 3,660,892

' SMET 5 BF 5 INVENTOIE TAKASHI TANAKA YUKI HI RO YANAGI UCHI ATTORNEYS METHOD FOR MAKING A MULTI-CI IANNEL MAGNETIC HEAD This invention relates to a method of making a multi-chantherebetween. Each of'the core members in one half matches up with a corresponding core member in the other half to form an elementary head of a ring type.

In such a construction method, it is difficult to match up the core members in one half exactly with the corresponding core members in the other half. When the tracks on the tapes to be recorded and reproduced by the elementary heads are narrow, the mismatching of core members is very serious. There is another conventional method of making a multichannel magnetic head. Two core members are matched up with each other on a flat surface of a plate so as to form an elementary head unit. Then, a plurality of elementary head units are stacked to make a multi-channel magnetic head. In such a construction method, it is comparatively easy to match up two core members with each other exactly, but it is difiicult to align the magnetic gaps in a straight line.

The track density of the tape which is recorded and reproduced by a conventional multi-channel magnetic head is limited by the winding space and the cross-talk between the elementary heads. However, the recent information storage requirements have increasingly required a higher track density and less cross-talk.

An object of the present invention is to provide a method of making a multi-channel magnetic head in which the core members are matched up exactly with corresponding core members.

Another object of the invention is to provide a method of making a multi-channel magnetic head in which all the magnetic gaps are aligned in one straight line.

A further object of the invention is to provide a method of making a multi-channel magnetic head which induces very little cross-talk between adjacent channels and can handle a tape with a high track density.

These objects are achieved by a method of making a multiwhich comprises the following steps:

I 1. providing a support plate having a flat surface;

2. providing a magnetic core having a winding wound thereon;

channel magnetic head according to the present invention 3. placing said wound magnetic core on said flat surface of spacer between the halves and with the core parts matched with the corresponding core parts in the other half.

These and other features of the invention will be apparent from the following detailed description taken together with the accompanying drawings, in which:

FIGS. 1 and 2 are perspective views showing a method of making an elementary unit of a multi-channel magnetic head I according to the present invention;

FIGS. 3 and 4 are a plan view and a front elevational view,

respectively, of a stack of the elementary units shown in FIG.

FIGS. 5 through 8 are perspective views showing further steps in the method of making a multi-channel magnetic head according to the present invention;

FIGS. 9 and 10 are perspective views of other kinds of elementary units which can be used in the method of making a multi-channel magnetic head according to the invention; and

FIGS. 11 and 12 are perspective views of stacks of other kinds of elementary unitswhich can be used in the method of making a multi-channel magnetic head according to the invention.

Referring to FIG. 1, reference character 20 designates a support plate which has two flat surfaces 21 and 21a and has two openings 22a and 22b. The support plate 20 is a laminated structure having a magnetic sheet 23 between non-magnetic sheets 24. Reference'characters 25a and 25b designate a C- shaped and an I-shaped core member, respectively. A winding 26 is wound on the C-shaped core member 25a.

The core members 25a and 25b are placed on the support plate 20 and joined with each other at 28 to form a ring core as shown in FIG. 2. One of said two openings 22a and 22b, for example, the opening 22a receives the winding 26. An elementary unit 27a is thereby formed. The other opening, for example, the opening 22b is adapted to receive a winding of an adjacent unit when a plurality of units are stacked in a manner described below.

A plurality of units 27a which are the same as that shown in FIG. 2, and a plurality of other units 27b which are in mirror image relationship with the units 27a are stacked alternatively as shown in FIGS. 3 and 4. The joints 28 of the C-shaped core members 25a and I-shaped core members 25b are nearly aligned in one straight line and lie between two planes 30a and 30b. The stacked elementary units are adhered to each other by any available and suitable adhesive or by casting.

Then the stacked elementary units are cut into two halves 29a and 2912 as shown in FIG. 5 along the planes 30a and 30b which are perpendicular to the support plates 20 and parallel to each other so that each of the ring cores formed by C- shaped core members 25a and I-shaped core members 25b are divided again into two parts 25c and 25d. All the joints 28 of the C-shaped 25a and I-shaped core members 25b between said two planes 30a and 30b are thus removed. In practice, the stack is cut by a blade as wide as the distance between the I planes 30a and 30b. The two planes are preferably spaced 0.1-1.0 mm from each other. Cut surfaces 31 are polished flat and smooth. Then said two halves 29 a and 29b are placed in face-to-face relationship with a. non-magnetic spacer 32 between them as shown in FIG. 6. The core parts 250 and 25d in one half 29 a match up again with corresponding core parts 25d and 25c in the other half 29b to form the elementary heads in a'ring type core. The spacer 32 forms magnetic gaps 33a, 33b, etc., between each pair of corresponding core parts. The width of the gaps 33a, 3312, etc., is substantially equal to the thickness of the spacer 32.

The composite body 34 shown in FIG. 6 is enclosed in a shield case 35 to protect the multi-channel magnetic head from undesired external fields, as shown in FIG. 7. Each of the plurality of windings 26 is connected to a tenninal pin 36 mounted on a terminal board 37. The terminal board 37 is attached to the shield case 35 as shown in FIG. 8.

Said C-shaped and I-shaped core members, said magnetic sheet forming the support plate, and said shield case may be composed of any suitable and available magnetic material, such as permalloy. Said non-magnetic sheets of the support plate and said spacer may be composed of any suitable and available non-magnetic material, such as BeCu.

Said C-shaped core member and said I-shaped core member match up exactly with each other even when said core members are thin because said two core members are joined with each other on one flat surface of said support plate. When the two halves of the stack are rejoined, the core parts in one half are made to match up exactly with the corresponding core parts in the other half by matching the halves at one point because each dimension on the cut surface of one half is exactly equal to the corresponding dimension on the cut surface of the other half. Moreover, it is obvious that the magnetic gaps are exactly aligned in one straight line.

For the same reasons, the magnetic sheets of the support plates in one half match up exactly with the corresponding magnetic sheets of the support plate in the other half. Therefore, the multi-channel magnetic head made by the method according to the present invention induces very little crosstalk between adjacent channels. Because the multi-channel magnetic head made by the method according to the present invention can have a small track width and a small space between the channels, it is able to handle a tape with a high track density. Said openings in the support plate help bring the individual units closer.

Referring to FIG. 9 wherein similar reference characters designate components similar to those of FIG. 2, two C- shaped core members 25a having windings 26 wound thereon are placed on a support plate 20. Openings 22 receive the windings 26. A plurality of units 27c which are the same as shown in FIG. 9 are stacked and adhered to each other. The steps following this step are the same as those described above.

Referring to FIG. 10, wherein similar reference characters designate components similar to those of FIG. 2, a ring core 25 without a magnetic gap and having windings 26 wound thereon is positioned on a support plate 20. A plurality of units 27d which are the same as shown in FIG. are stacked and adhered to each other. The steps following this step are the same as those described above.

Because the core 25 consists of one member and has no joint, there is a large tolerance in the alignment position of elementary units in the stacking process and in the cutting position of the stack of elementary units.

Referring to FIG. 11, four elementary units 38a and 38b are stacked together in a staggered arrangement to form a multichannel magnetic head. Each elementary unit 38a or 38b comprises a ring core 25 without a magnetic gap, a winding 26 wound on the core 25 and a support plate on which the core is placed. The elementary units 38a and 38b are in mirror image relationship with each other. Each pair of adjacent units 38a and 38b are offset from the other; alternate units 38a and 38a or 38b and 38b are aligned with each other and have an open space 39 between them. Electrical parts (not shown) other than the parts of said magnetic head are accommodated in the open space 39. The electrical parts are preferably a transformer and/or an amplifier in the form of an integrated circuit which cooperate with each winding 26. A combined transformer can reduce the number of turns of the winding 26 as well as the cross-talk. The stack is cut at the plane 40, shown by broken lines in FIG. 11, which is perpendicular to the support plates 20 and which divides each ring core 25 into two parts, C-shaped part 250 and I-shaped part 25d. The steps following this step are the same as those described above.

Referring to FIG. 12 wherein similar reference characters designate components similar to those of the foregoing figures, each ring core 25 with a winding 26 is placed on a flat surface 21 of a support plate 20a. The support plate 20a has a thinner portion 41 and a thicker portion 42. A plurality of elementary units are stacked in a staggered arrangement as shown in FIG. 12. The thinner portion 41 of each said support plate 20a overlies the next lower support plate 20a, and the thicker portion 42 overlaps an edge 43 of the next lower support plate 20a or extends below the upper surface 21 of the next lower support plate 20a and abuts the edge 43 of said next lower support plate 20a. Such a construction makes it easy to stack a plurality of elementary units. The stack is cut in a plane 40, shown by the broken line in FIG. 11, which is perpendicular to the flat surfaces 21 of the support plates 20a and which divides each ring core 25 into two parts, C-shaped part 25c and I-shaped part 25d. The steps following this step are same as those described above.

What is claimed is: 1. A method of making a multi-channel magnetic head comprising:

l. providing a support plate having a flat surface, at least the flat surface being of non-magnetic material;

2. providing a magnetic core having a winding wound thereon;

3. placing said wound magnetic core on said flat surface of said support plate to make an elementary unit;

. stacking a plurality of said elementary units one on the other;

. adhering said stacked elementary units to each other;

. cutting said stack into two halves in at least one plane which is perpendicular to said flat surfaces of said support plates and which divides each of said magnetic cores into two parts;

7. placing a spacer of non-magnetic material between said halves; and

8. rejoining said two halves at the plane of the cut with the spacer between them and with the core parts in one half matching the corresponding core parts in the other half.

2. A method of making a multi-channel magnetic head as claimed in claim 1, wherein said magnetic core is a ring core having no gap therein.

3. A method of making a multi-channel magnetic head as claimed in claim 1, wherein said magnetic core consists of two core members which are joined with each other into a ring type core on said flat surface of said support plate.

4. A method of making a multi-channel magnetic head as claimed in claim 3, wherein said stacked elementary units are cut in two planes which are perpendicular to the support plates and parallel to each other so that each of the joints between said two core members is between said two parallel planes.

5. A method of making a multi-channel magnetic head as claimed in claim 3, wherein said two planes are spaced from 0.1 to 1.0 mm from each other. 

1. A method of making a multi-channel magnetic head comprising:
 1. providing a support plate having a flat surface, at least the flat surface being of non-magnetic material;
 2. providing a magnetic core having a winding wound thereon;
 3. placing said wound magnetic core on said flat surface of said support plate to make an elementary unit;
 4. stacking a plurality of said elementary units one on the other;
 5. adhering said stacked elementary units to each other;
 6. cutting said stack into two halves in at least one plane which is perpendicular to said flat surfaces of said support plates and which divides each of said magnetic cores into two parts;
 7. placing a spacer of non-magnetic material between said halves; and
 8. rejoining said two halves at the plane of the cut with the spacer between them and with the core parts in one half matching the corresponding core parts in the other half.
 2. providing a magnetic core having a winding wound thereon;
 2. A method of making a multi-channel magnetic head as claimed in claim 1, wherein said magnetic core is a ring core having no gap therein.
 3. A method of making a multi-channel magnetic head as claimed in claim 1, wherein said magnetic core consists of two core members which are joined with each other into a ring type core on said flat surface of said support plate.
 3. placing said wound magnetic core on said flat surface of said support plate to make an elementary unit;
 4. stacking a plurality of said elementary units one on the other;
 4. A method of making a multi-channel magnetic head as claimed in claim 3, wherein said stacked elementary units are cut in two planes which are perpendicular to the support plates and parallel to each other so that each of the joints between said two core members is between said two parallel planes.
 5. A method of making a multi-channel magnetic head as claimed in claim 3, wherein said two planes are spaced from 0.1 to 1.0 mm from each other.
 5. adhering said stacked elementary units to each other;
 6. cutting said stack into two halves in at least one plane which is perpendicular to said flat surfaces of said support plates and which divides each of said magnetic cores into two parts;
 7. placing a spacer of non-magnetic material between said halves; and
 8. rejoining said two halves at the plane of the cut with the spacer between them and with the core parts in one half matching the corresponding core parts in the other half. 